docs: def get_stddevs(self, mean, stddev_types):
          """
          Returns the standard deviations from mean (pg 164; more robust than
          estimate using magnitude)
          """
          mean = np.exp(mean)
          sigma = 0.39 + np.zeros(mean.shape)
          sigma[mean < 0.068] = 0.55
          idx = np.logical_and(mean >= 0.068, mean <= 0.21)
          sigma[idx] = 0.173- 0.140 * np.log(mean[idx])
          stddevs = []
          for stddev in stddev_types:
              if stddev == const.StdDev.TOTAL:
                  stddevs.append(sigma)
          return stddevs